To begin with i would like to tell you that even i work in nuclear medicine, about 8 hours a day for the past 5 years. I am doing just fine. :). I known people who worked for over 40 years.
Coming to scientific explanation, you are exposed to radiation
because of your occupation. (Occupational radiation exposure). You must be provided with TLD badge, which is changed every 3 months. You must also be taught the safe handling of radioactivity.
If all the safety precautions are followed, people exposed to radiation during their occupation, dont have increased risk of cancer compared to others.
You must also remember that almost everyone in this world is exposed to radiation (natural background radiation) which is in the scale of 3-5 mSv. Because of your occupation, you might receive an additional 1 to 1.5 mSv per year which is not dangerous.